Line one 9x13 inch pan with aluminum foil sprayed with non-stick spray.
In a microwave safe bowl, combine the chocolate chips, butterscotch or peanut butter chips, condensed milk and salt.
Microwave on high for 2 minutes. Remove, stir, and heat on high for 1 to 2 minutes longer. Remove and stir until all chips are melted.
Add vanilla and mix well; pour into prepared pan. Chill in refrigerator overnight, or until set. Remove foil, slice and serve.